1. Field of the Invention
The present invention relates to a wafer drying apparatus which performs drying processing on a wafer such as a semiconductor wafer and a method for drying a wafer using the wafer drying apparatus, and, more particularly, a wafer drying apparatus which performs drying by blowing air to a wafer and a method for drying a wafer using the wafer drying apparatus.
2. Description of the Related Art
Conventionally, both surfaces of a square substrate such as a liquid crystal substrate subjected to wet surface treatment have been dried by blowing air to the square substrate from a slit-shaped gas jetting port while the square substrate are horizontally conveyed (see, for example, Patent Literature 1 and Patent Literature 2).
Further, silicon wafer processing process also includes process of performing drying processing. For example, in process in which a slurry, drug solution, or the like, is used, a wafer gets wet, and this wet wafer is dried or cleaned and dried during intermediate or final process of processing for various purposes.
The purposes of drying in the intermediate process include improving a cleanliness level of the wafer, facilitating conveyance to the next process, adapting the wafer to an intermediate quality examination, and the like.
Further, the purposes of drying in the final process include improving a cleanliness level of the wafer, adapting the wafer to a final quality examination, adapting the wafer to shipment, and the like.
While, typically, different drying methods are selected according to purposes of each process or adapted cleaning, typical drying methods include air blow, spin drying, IPA steam drying, IPA direct substitution, vacuum/reduced-pressure drying, Marangoni drying, and the like.
In the present invention, attention is not focused on the final process in which a strict cleanliness level is required, but is focused on the intermediate process. In the intermediate process in which requirements for the cleanliness level are not strict, in order to reduce equipment cost and to improve productivity, a cleaning and drying method which is as simple as possible according to the purposes are desirable.
On the background as described above, drying has been implemented with an apparatus having a simple structure as illustrated in FIG. 5.
That is, both surfaces of a wafer 220 are dried at the same time by blowing air 212 while making the wafer 220 pass upward between two pipes (a first air supply tube 204 and a second air supply tube 206) respectively having a plurality of air outlets (a first air outlet 208 and a second air outlet 210) separated from each other at predetermined intervals.
In this manner, droplets on a surface of the wafer 220 move downward as the wafer 220 moves upward by the blown air 212 and gravity, and drop from the wafer 220.
Then, when the wafer 220 completely passes between the two pipes (the first air supply tube 204 and the second air supply tube 206), drying of the whole surface of the wafer 220 is finished.
It should be noted that FIG. 5(a) is a diagram of a drying apparatus 200 viewed from a side, and FIG. 5(b) is a diagram of the drying apparatus 200 viewed from the side when the drying apparatus 200 in FIG. 5(a) is rotated by 90 degree in a horizontal direction.